Nationally Notifiable Infectious Diseases and Conditions, United States: Annual Tables

TABLE 3. Annual reported cases of notifiable diseases, by month*, United States, excluding U.S. Territories and Non-U.S. Residents, 2021
Disease Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Unknown Total
Anthrax — — — — — — — — — — — — — —
Arboviral diseases
Chikungunya virus disease 2 — 2 1 1 5 3 3 2 7 3 6 — 35
Eastern equine encephalitis virus disease
Neuroinvasive — — — — — — 1 1 — 3 — — — 5
Non-neuroinvasive — — — — — — — — — — — — — —
Jamestown Canyon virus disease
Neuroinvasive — — — — 2 4 3 3 3 2 3 1 — 21
Non-neuroinvasive — — — 1 — — 2 1 6 1 — — — 11
La Crosse virus disease
Neuroinvasive — — — 1 — 3 13 9 9 3 1 — — 39
Non-neuroinvasive — — — — — — — — 1 — — — — 1
Powassan virus disease
Neuroinvasive — — — 2 5 4 6 1 — 2 3 1 — 24
Non-neuroinvasive — — — — — — 1 — — — — — — 1
St. Louis encephalitis virus disease
Neuroinvasive — — — — — — — 1 1 7 1 1 — 11
Non-neuroinvasive — — — — — — — — — 5 — 1 — 6
West Nile virus disease
Neuroinvasive — 2 2 — 4 11 60 253 662 868 118 27 — 2,007
Non-neuroinvasive — — — 1 3 5 30 119 210 407 105 19 — 899
Western equine encephalitis virus disease
Neuroinvasive — — — — — — — — — — — — — —
Non-neuroinvasive — — — — — — — — — — — — — —
Babesiosis
Total 18 11 8 29 88 336 1,123 507 207 155 103 89 — 2,674
Confirmed 16 6 3 15 74 318 1,054 467 184 127 89 76 — 2,429
Probable 2 5 5 14 14 18 69 40 23 28 14 13 — 245
Botulism
Total 15 18 21 15 26 27 23 14 26 20 8 23 — 236
Foodborne 2 1 2 — — 4 — 1 5 1 1 3 — 20
Infant 13 12 15 10 24 17 17 11 16 14 7 15 — 171
Other (wound & unspecified) — 5 4 5 2 6 6 2 5 5 — 5 — 45
Brucellosis 5 3 8 12 9 14 14 9 12 9 5 14 — 114
Campylobacteriosis 2,706 3,053 3,299 3,873 5,917 6,773 9,523 6,334 5,429 6,511 4,576 5,415 — 63,409
Candida auris, clinical † 32 29 39 38 46 50 66 55 53 70 47 83 — 608
Carbapenemase-producing carbapenem-resistant Enterobacteriaceae 192 139 171 142 207 179 226 197 185 276 180 234 — 2,328
Chancroid 2 — — — — 1 — — — — — — — 3
Chlamydia trachomatis infection 126,718 122,803 128,462 125,800 158,114 122,621 157,900 127,251 123,320 160,356 118,403 142,092 — 1,613,840
Cholera — — — — — — — 2 1 1 — 1 — 5
Coccidioidomycosis 1,902 1,869 1,772 1,494 1,711 1,371 1,758 1,368 1,282 1,788 1,635 2,251 — 20,201
Coronavirus Disease 2019 (COVID-19)
Total 5,268,641 2,215,637 1,646,278 1,767,606 1,023,051 379,190 1,703,081 4,180,860 3,918,937 2,749,051 2,517,157 8,465,745 261,260 36,096,494
Confirmed 4,385,310 1,760,323 1,289,581 1,415,002 804,420 293,704 1,341,842 3,289,321 3,065,420 2,186,347 2,016,912 7,029,833 198,253 29,076,268
Probable § 883,331 455,314 356,697 352,604 218,631 85,486 361,239 891,539 853,517 562,704 500,245 1,435,912 63,007 7,020,226
Cryptosporidiosis
Total 372 398 445 553 701 623 1,388 1,176 967 1,091 673 768 — 9,155
Confirmed 253 286 329 410 553 493 1,090 942 795 912 527 601 — 7,191
Probable 119 112 116 143 148 130 298 234 172 179 146 167 — 1,964
Cyclosporiasis 7 12 7 7 60 531 1,084 422 139 81 17 57 — 2,424
Dengue virus infections 
Dengue 11 5 3 6 7 9 18 15 14 36 28 30 — 182
Dengue-like illness — — — — — — — — 2 3 2 — — 7
Severe dengue — — — — — — — — 2 1 1 — — 4
Diphtheria — — — — — — — — — — — — — —
Ehrlichiosis and Anaplasmosis
Anaplasma phagocytophilum infection 15 14 30 224 737 1,569 2,027 580 268 464 526 275 — 6,729
Ehrlichia chaffeensis infection 12 5 10 43 144 266 418 178 102 80 34 45 — 1,337
Ehrlichia ewingii infection — — — — 3 2 7 3 3 — 1 — — 19
Undetermined ehrlichiosis/anaplasmosis — — — — 11 13 30 12 5 5 1 — — 77
Giardiasis 472 605 750 710 918 815 1,321 1,199 1,270 1,371 965 1,247 — 11,643
Gonorrhea 57,070 54,344 54,769 53,745 67,358 53,996 69,107 54,241 53,714 68,681 50,433 62,127 — 699,585
Haemophilus influenzae, invasive disease
All ages, all serotypes 138 155 153 201 245 186 255 208 244 340 326 591 — 3,042
Age <5 years
Serotype b 2 4 2 2 2 1 2 1 2 3 2 4 — 27
Non-b serotype 5 8 9 16 12 13 9 4 11 17 13 20 — 137
Nontypeable 3 3 5 12 7 5 1 9 7 14 7 21 — 94
Unknown serotype 6 9 4 8 17 19 17 13 13 17 13 36 — 172
Hansen's disease 5 5 2 3 7 7 4 6 2 8 2 6 — 57
Hantavirus infection, non-hantavirus pulmonary syndrome ** — — — — — 1 1 — — — — — — 2
Hantavirus pulmonary syndrome — — 2 1 2 1 — 3 2 2 — 1 — 14
Hemolytic uremic syndrome post-diarrheal 8 4 11 23 26 26 42 36 25 38 23 40 — 302
Hepatitis, Viral Disease ††
Hepatitis A 522 603 586 574 687 509 492 325 341 440 263 384 — 5,726
Hepatitis B
Acute 120 164 163 151 207 163 198 137 140 206 128 267 — 2,044
Perinatal infection 1 1 2 1 2 1 4 — — 2 2 1 — 17
Hepatitis C
Acute 426 453 532 493 641 464 588 441 420 545 410 615 — 6,028
Confirmed 361 384 436 416 523 391 483 352 356 452 353 516 — 5,023
Probable 65 69 96 77 118 73 105 89 64 93 57 99 — 1,005
Perinatal infection 16 10 19 25 21 16 20 13 10 20 12 18 — 200
Human immunodeficiency virus diagnoses 2,578 2,510 3,101 3,046 2,872 3,269 3,047 2,973 2,834 2,525 1,956 558 — 31,269
Influenza-associated pediatric mortality — — 3 — 1 — — — — — — 2 — 6
Invasive pneumococcal disease §§
All ages 710 595 663 815 1,116 729 865 750 883 1,249 1,360 2,363 — 12,098
Confirmed 699 582 644 791 1,100 713 845 735 867 1,221 1,321 2,314 — 11,832
Probable 11 13 19 24 16 16 20 15 16 28 39 49 — 266
Age <5 years 20 23 34 54 71 64 62 53 70 93 99 127 — 770
Confirmed 20 23 33 50 69 59 60 51 68 88 94 124 — 739
Probable — — 1 4 2 5 2 2 2 5 5 3 — 31
Legionellosis ¶¶ 276 297 304 369 572 786 1,707 884 1,022 1,055 546 624 — 8,442
Leptospirosis 2 7 7 4 3 4 7 5 10 4 7 9 — 69
Listeriosis ***
Total 43 56 47 48 70 80 148 87 120 110 71 97 — 977
Confirmed 42 51 45 45 67 78 142 86 117 107 68 93 — 941
Probable 1 5 2 3 3 2 6 1 3 3 3 4 — 36
Lyme disease
Total 590 544 714 883 1,747 3,701 6,874 3,522 1,900 1,882 1,171 1,082 — 24,610
Confirmed 378 317 439 510 1,063 2,336 4,744 2,444 1,241 1,273 774 692 — 16,211
Probable 212 227 275 373 684 1,365 2,130 1,078 659 609 397 390 — 8,399
Malaria 65 61 42 74 127 135 189 200 203 193 96 118 — 1,503
Measles †††
Total — — — 2 — — 1 — 19 26 — — — 48
Indigenous — — — 1 — — 1 — 1 26 — — — 29
Imported — — — 1 — — — — 18 — — — — 19
Meningococcal disease
All serogroups 13 12 15 10 29 18 17 14 18 20 13 29 — 208
Serogroups ACWY 4 3 7 7 13 7 8 6 7 9 4 8 — 83
Serogroup B 3 4 1 1 3 — 2 5 2 2 — 9 — 32
Other serogroups 2 1 3 1 — 2 — — 1 1 3 2 — 16
Unknown serogroup 4 4 4 1 13 9 7 3 8 8 6 10 — 77
Mumps 6 8 14 10 10 13 19 16 29 22 15 27 — 189
Novel Influenza A virus infections 1 — 1 1 2 — — 3 2 5 1 — — 16
Pertussis 80 87 104 127 188 207 208 163 200 252 233 267 — 2,116
Plague §§§ — — — — — — 2 1 1 — — — — 4
Poliomyelitis, paralytic — — — — — — — — — — — — — —
Poliovirus infection, nonparalytic — — — — — — — — — — — — — —
Psittacosis — — 1 — — — 1 1 — — 1 — — 4
Q fever
Total 13 5 12 19 27 21 25 15 4 19 13 19 — 192
Acute 11 4 11 14 24 20 21 13 4 16 13 14 — 165
Chronic 2 1 1 5 3 1 4 2 — 3 — 5 — 27
Rabies
Animal 167 153 274 308 352 362 369 442 453 329 230 202 — 3,641
Human 1 1 — — — — — 1 — — 2 — — 5
Rubella — — — 1 — 1 1 2 1 — — 1 — 7
Rubella, congenital syndrome — — — — — — — — — — — — — —
Salmonella Paratyphi infection ¶¶¶ 3 2 4 9 6 5 10 3 3 5 5 9 — 64
Salmonella Typhi infection **** 2 15 16 20 24 26 23 27 17 26 14 24 — 234
Salmonellosis (excluding S. Typhi infection and S. Paratyphi infection) †††† 1,625 1,533 1,910 2,688 3,982 4,405 7,020 5,588 6,003 6,698 3,652 4,145 — 49,249
Severe acute respiratory syndrome-associated coronavirus disease — — — — — — — — — — — — — —
Shiga toxin-producing Escherichia coli (STEC) 424 421 583 829 1,375 1,418 2,407 1,641 1,314 1,448 964 1,119 — 13,943
Shigellosis 420 494 513 584 874 771 1,182 923 948 1,171 954 1,165 — 9,999
Smallpox — — — — — — — — — — — — — —
Spotted fever rickettsiosis
Total 17 20 22 50 154 207 270 151 125 110 61 70 — 1,257
Confirmed — 1 — 3 8 8 8 5 5 3 2 — — 43
Probable 17 19 22 47 146 199 262 146 120 107 59 70 — 1,214
Streptococcal toxic shock syndrome 8 18 11 18 18 11 10 11 9 11 7 13 — 145
Syphilis
Total, all stages §§§§ 12,172 12,420 13,361 13,339 16,956 13,420 17,043 13,919 13,413 18,228 13,314 16,782 — 174,367
Congenital ¶¶¶¶ 196 207 235 209 200 219 200 243 259 286 262 304 — 2,820
Primary and secondary 3,720 3,880 3,965 4,091 5,132 4,197 5,239 4,269 4,068 5,543 3,905 5,025 — 53,034
Tetanus 1 2 2 2 5 3 4 2 — 2 3 2 — 28
Toxic shock syndrome (other than Streptococcal) 1 — — 2 — 2 1 2 3 — 1 3 — 15
Trichinellosis — — — 1 — — — 1 — — — — — 2
Tuberculosis 368 489 548 591 724 688 818 572 619 794 601 1,070 — 7,882
Tularemia — 2 1 10 21 26 42 19 7 17 8 9 — 162
Vancomycin-intermediate Staphylococcus aureus 6 10 9 6 12 2 6 2 7 2 6 5 — 73
Vancomycin-resistant Staphylococcus aureus ***** — — — — 1 1 — — — — — 3 — 5
Varicella morbidity 198 195 228 264 399 275 277 228 304 448 279 401 — 3,496
Varicella mortality — — — — — — — — 1 — — — — 1
Vibriosis
Total 46 50 77 110 168 296 658 407 314 326 184 217 — 2,853
Confirmed 21 23 30 43 74 178 415 256 193 157 72 94 — 1,556
Probable 25 27 47 67 94 118 243 151 121 169 112 123 — 1,297
Viral hemorrhagic fevers
Crimean-Congo hemorrhagic fever virus — — — — — — — — — — — — — —
Ebola virus — — — — — — — — — — — — — —
Guanarito virus — — — — — — — — — — — — — —
Junin virus — — — — — — — — — — — — — —
Lassa virus — — — — — — — — — — — — — —
Lujo virus — — — — — — — — — — — — — —
Machupo virus — — — — — — — — — — — — — —
Marburg virus — — — — — — — — — — — — — —
Sabia virus — — — — — — — — — — — — — —
Yellow fever — — — — — — — — — 1 — — — 1
Zika virus
Zika virus disease, congenital ††††† — — — — — — — 1 — — — — — 1
Zika virus disease, non-congenital — — — 1 — — — 1 — — — — — 2
Zika virus infection, congenital ††††† — — — — — — — — — — — — — —
Zika virus infection, non-congenital — — — — — — — — — — — — — —
  • —: No reported cases — The reporting jurisdiction did not submit any cases to CDC.
  • * Month is defined using MMWR week (https://ndc.services.cdc.gov/wp-content/uploads/2021/02/MMWR_Week_overview.pdf). MMWR week calendars can be found at https://ndc.services.cdc.gov/event-codes-other-surveillance-resources/.
  • † Candida auris colonization/screening cases are not included in this table. These data are available on the Mycotic Diseases Branch's Tracking Candida auris page (https://www.cdc.gov/fungal/candida-auris/tracking-c-auris.html)
  • § Of the reporting areas that submitted 2021 aggregate COVID-19 data to CDC, two did not submit probable cases. New York (excluding New York City) and U.S. Virgin Islands did not collect probable cases.
  • ¶ Counts include confirmed and probable dengue cases.
  • ** Case counts may include Old World hantavirus infections, such as Seoul virus.
  • †† Chronic hepatitis B and chronic hepatitis C data are not included in NNDSS tables but reported case counts are included in the annual Viral Hepatitis Surveillance Report, 2021, published online by CDC's Division of Viral Hepatitis, available at https://www.cdc.gov/hepatitis/statistics/SurveillanceRpts.htm.
  • §§ Counts include drug resistant and susceptible cases of Invasive Pneumococcal Disease. This condition was previously named Streptococcus pneumoniae invasive disease and cases were reported to CDC using different event codes to specify whether the cases were drug resistant or in a defined age group, such as <5 years.
  • ¶¶ Beginning in 2020, the CSTE case definition changed such that cases diagnosed by PCR were classified as confirmed, whereas previously those cases were classified as suspect and did not meet the publication/print criteria.
  • *** Before 2019, probable cases were not reported, and cases in neonates ≤60 days of age were counted as one case in a mother-infant pair. Beginning in 2019, confirmed and probable cases are being reported, and maternal and neonatal cases are being counted separately.
  • ††† Measles is considered imported if the disease was acquired outside of the United States and is considered indigenous if the disease was acquired anywhere within the United States or it is not known where the disease was acquired.
  • §§§ Beginning in 2020, confirmed and probable plague cases began to be combined and published.
  • ¶¶¶ Beginning in January 2019, cases began to be reported as Salmonella Paratyphi infection. In 2018, cases were reported as paratyphoid fever. Prior to 2018, cases of paratyphoid fever were considered salmonellosis.
  • **** Beginning in January 2019, cases began to be reported as Salmonella Typhi infection. In previous years, cases were reported as typhoid fever.
  • †††† Beginning in January 2019, cases began to be reported as salmonellosis (excluding Salmonella Typhi infection and Salmonella Paratyphi infection). In 2018, cases were reported as salmonellosis (excluding paratyphoid fever and typhoid fever). Prior to 2018, cases of paratyphoid fever were considered salmonellosis.
  • §§§§ Includes the following categories: primary; secondary; early non-primary non-secondary (includes cases previously reported as early latent); unknown duration or late (includes cases previously reported as late latent syphilis and cases previously reported as late syphilis with clinical manifestations) and congenital syphilis.
  • ¶¶¶¶ Congenital syphilis cases are usually assigned to the mother's state of residence at the time of delivery. Data for congenital syphilis are aggregated by the infant's year of birth.
  • ***** Vancomycin-resistant Staphylococcus aureus cases reported in this table may not have been verified by CDC. CDC verified 2 vancomycin-resistant Staphylococcus aureus cases in 2021.
  • ††††† Data reported to ArboNET using the national surveillance case definition for congenital Zika virus infection (CSTE Position Statement 16-ID-01).
Notes:
  1. These are annual cases of selected infectious national notifiable diseases from the National Notifiable Diseases Surveillance System (NNDSS). NNDSS data reported by the 50 states, New York City, the District of Columbia, and the U.S. territories are collated and published. Cases are reported by state health departments to CDC weekly. Because source datasets may be updated as additional information is received, statistics in publications based on that source data may differ from what is presented in these tables. Source datasets for the 2021 annual tables were officially closed on March 29, 2023.
  2. The list of national notifiable Infectious diseases and conditions for 2021 and their national surveillance case definitions are available by navigating to the Surveillance Case Definitions | CDC web page, selecting "2021" for the notifiable condition list year, checking "Infectious" conditions, and clicking "Get Notifiable List by Year". CSTE adopted the first coronavirus disease 2019 (COVID-19) national surveillance case definition on April 5, 2020, and they approved a revision to the COVID-19 national surveillance case definition, effective August 5, 2020. On June 17, 2021, a revision to the COVID-19 national surveillance case definition was approved, effective September 1, 2021. Publication criteria for the finalized 2021 data are available at https://wonder.cdc.gov/nndss/documents/2021_NNDSS_Publication_Criteria_03162022.pdf. See also Guide to Interpreting Provisional and Finalized NNDSS Data.
  3. Population estimates for incidence rates are July 1st, 2020, estimates obtained from the National Center for Health Statistics (NCHS) postcensal estimates of the resident population of the United States for April 1, 2010, to July 1, 2020, by year, county, single year of age (range: 0 to 85 years), bridged-race (white, black or African American, American Indian or Alaska Native, Asian, or Pacific Islander), Hispanic ethnicity (not Hispanic or Latino, Hispanic or Latino), and sex (Vintage 2020), prepared under a collaborative arrangement with the U.S. Census Bureau. Population estimates for states released September 22, 2021, are available at https://www.cdc.gov/nchs/nvss/bridged_race/data_documentation.htm. Population estimates for territories are the 2020 mid-year estimates from the U.S. Census Bureau International Data Base, accessed on March 15, 2022, at https://www.census.gov/data-tools/demo/idb/#/country?YR_ANIM=2022. The choice of population denominators for incidence is based on the availability of population data at the time of publication preparation.
  4. Annual tables for 2016 and later years are available on CDC WONDER.
  5. Annual summary reports from 1993–2015 are available as published in the Morbidity and Mortality Weekly Report.
  6. NNDSS annual tables since 1952 are available at CDC Stacks (once in CDC Stacks, select "Annual Reports" in the "Genre" box to the left).
  7. For most conditions, national incidence rates are calculated as the number of reported cases for each infectious disease or condition divided by the U.S. resident population for the specified demographic population or the total U.S. resident population, multiplied by 100,000. When a national notifiable infectious condition is associated with a specific age restriction, the same restriction was applied to the population in the denominator of the incidence rate calculation. In addition, population data from reporting jurisdictions in which the disease or condition was not reportable or not available were excluded from the denominator of the incidence rate calculations.

    Age restrictions in the numerator and denominator are applied for the following childhood conditions:

    • Zika virus disease, congenital (age restriction in numerator and denominator is <1 year)
    • Zika virus infection, congenital (age restriction in numerator and denominator is <1 year)
    • Haemophilus influenzae, invasive disease <5 years (age restriction in numerator and denominator is <5 years)
    • Invasive pneumococcal disease <5 years (age restriction in numerator and denominator is <5 years)
    • Influenza associated pediatric mortality (age restriction in numerator and denominator is <18 years)
    • Infant botulism (age restriction in numerator and denominator is <1 year)
    • Congenital rubella syndrome (age restriction in numerator and denominator is <1 year)
    • Perinatal hepatitis B infection (age restriction in numerator and denominator is ≤24 months)
    • Perinatal hepatitis C infection (age restriction in numerator and denominator is ≤36 months).

    Data for congenital syphilis are aggregated by the infant's year of birth. The rate for congenital syphilis is based upon the number of reported cases per 100,000 live births, using natality data for 2021 (National Center for Health Statistics Natality 2021, as compiled from data provided by the Vital Statistics Cooperative Program). Congenital syphilis cases are usually assigned to the mother's state of residence at the time of delivery. The mother's race and ethnicity are used for race- and ethnicity-specific rates of congenital syphilis cases.

  8. Surveillance data reported by other CDC programs might vary from data reported in these tables because of differences in 1) the date used to aggregate the data, 2) the timing of reports, 3) the source of the data, 4) surveillance case definitions, and 5) policies regarding case jurisdiction (i.e., which jurisdiction should submit the case notification to CDC).
  9. Disease data presented in the 2021 tables reflect impacts of the COVID-19 pandemic, such as changes in exposure-related behavior, healthcare-seeking behavior, disease reporting, and public health investigations.
Suggested Citation: Acknowledgment:
  • CDC acknowledges the local, state, and territorial health departments that collected the data from a range of case ascertainment sources (e.g., healthcare providers, hospitals, laboratories) and reported these data to CDC's National Notifiable Diseases Surveillance System.